Type I Diabetes

1. Type I Diabetes Kris Hinnerichs

2. Diabetes Mellitus • A condition where the body is no longer able to control the glucose levels in the blood stream • ~16 mill. cases in the United States • 5-10% of those cases are type I • Half of these cases are under age 20

3. Physiology • Endocrine is Greek • Endo = within • Krino = to separate • Intercellular chemical signals are produced within and secreted from endocrine glands, but have an effect away from the gland • Only effects target cells

4. Negative Feedback Homeostasis of blood glucose levels • Blood glucose levels increase after a meal  Insulin is secreted • Insulin causes tissues to take up glucose  blood glucose levels decline • Rate of insulin secretion declines too  rate of blood glucose uptake decreases

5. Endocrine Part of Pancreas • Pancreatic islets (islets of Langerhans) dispersed among exocrine portion • Beta cells secrete insulin • Alpha cells secrete glucagon • Both work to regulate blood nutrient levels

6. Low Blood Glucose Levels • Nervous system malfunctions • Fats and proteins are broken down causing ketoacidosis • pH drops • Ketones enter the blood stream • Amino acids are broken down and used to synthesize glucose by the liver

7. High Blood Glucose Levels • Kidneys produce large volumes of urine • Urine is high in glucose molecules • Frequent urination can lead to dehydration

8. Increase Elevated blood glucose levels Parasympathetic stimulation / digestion Blood levels of certain amino acids Decrease Decreased blood glucose levels Sympathetic stimulation / exercise Insulin Secretion

9. Target Cells / Tissues • Liver • Adipose tissues • Muscles • Satiety center of hypothalamus • Glucose is converted to glycogen or fat, and the amino acids are used to synthesize protein

10. Glucagon • Released from alpha cells when blood glucose levels are low • Bind to membrane-bound receptors in the liver to cause the conversion of glycogen stored in the liver to glucose • Glucose is then released into the blood to increase blood glucose levels

11. Target Tissues Insulin Responses Glucagon Responses Skeletal muscle, cardiac muscle, cartilage, bone fibroblasts, blood cells and mammary glands Increases glucose uptake and glycogen synthesis; increases uptake of amino acids Has little effect Liver Increases glycogen synthesis; increases use of glucose for energy Causes rapid increase in the breakdown of glycogen to glucose and release of glucose into the blood; increases the formation of glucose from amino acids and, to some degree, from fats; increases metabolism of fatty acids Adipose cells Increases glucose uptake, glycogen synthesis, fat synthesis High concentrations cause breakdown of fats; probably unimportant under conditions Nervous system Has little effect except to increase glucose uptake in the satiety center Has no effect Effects of Insulin and Glucagon on Target Tissues

12. Hormone Source Main Actions During Exercise Epinephrine Adrenal Medulla Stimulation of muscle, and to a lesser extend, liver, glycogen breakdown, and mobilization of free fatty acids from adipose tissues; more is released with increasing exercise intensity Norepinephrine Adrenal Medulla, Sympathetic Nerve Endings Stimulation of liver to produce new glucose from available precursors; “feedforward” control of glucose along with epinephrine Glucagon Pancreas Stimulation of liver glycogen breakdown and new glucose production from precursors to increase glucose output; changes in the insulin to glucagons ration largely affect glycemia Growth Hormone Anterior Pituitary Direct stimulation of fat metabolism (release of free fatty acids from adipose) and indirect suppression of glucose use; stimulation of amino acid storage Cortisol Adrenal Cortex Mobilization of amino acids and glycerol as precursors for hepatic glucose production and release of free fatty acids for muscle use Blood Glucose-Raising Hormones During Exercise

13. Pathophysiology • Diabetes mellitus is characterized by glucose concentrations in the blood that are high enough to overwhelm the reabsorption capabilities of the kidneys • Glycosuria—glucose in urine • Polyuria—excessive urine production • Other metabolic products are present in abnormal concentrations

14. Causes • Researchers are uncertain of causes • Possibilities: • Genetic abnormalities • Pathological conditions • Injuries • Immune disorders • Hormonal imbalances • Secretion of too little insulin • Insufficient numbers of insulin receptors • Defective receptors

15. Without Insulin… • Cells cannot absorb glucose • After meals, blood concentrations become so elevated that the kidneys cannot reclaim all the glucose • High urinary concentrations of glucose limit ability to conserve water • High urinary concentrations of glucose cause frequent urination and possible dehydration

16. Without insulin… • Chronic dehydration can cause neural function and muscle weakness • Satiety center of brain responds with an exaggerated appetite • Endocrine tissues respond with more glucose • Ketoacidosis results

17. Long Term Therapy • Dietary control and insulin • Complications: • Tissue glucose demands cycle • Meals • Physical activity • Emotional state • Stress • Other unpredictable factors

18. Diabetic Coma • Cause—loss of NA+, K+, and ketone bodies through excessive urination • S/S—labored breathing, gasping for air, fruity –smelling breath, nausea, vomiting, thirst, flushed skin, confusion, unconsciousness • Care—early detection of ketoacidosis, injection of insulin

19. Insulin Shock • Cause—too much insulin in the body results in hypoglycemia • S/S—tingling sensations, physical weakness, headaches, abdominal pain, rapid HR, tremors, drowsiness • Care—adhere to a carefully planned diet with a snack before activity, keep a sugar source available

20. Pharmacology • Insulin is the main drug • Insulin is a protein hormone and must be injected Refer to charts in handout

21. Exercise and Type I Diabetes • Controversial • Does not improve glycemic control • Reduce the risk of complications due to diabetes • Before beginning any program, make sure to undergo a medical evaluation • Macrovascular complications • Microvascular complications

22. Cardiovascular System • A graded exercise test may be helpful • Age > 35 • Type I diabetes of > 15 years • Presence of any additional risk factors for coronary artery disease • Presence of microvascular disease • Peripheral vascular disease • Autonomic neuropathy

23. PAD • Peripheral Arterial Disease • Evaluation is based on signs and symptoms • Intermittent claudication • Cold feet • Decreased or absent pulses • Atrophy of subcutaneous tissues • Hair loss

24. Retinopathy • The eye examination schedule should follow the ADA’s Clinical Practice Guidelines • See chart • Those with proliferative diabetic retinopathy should avoid strenuous exercise • Anaerobic exercise • Exercise involving straining, jarring, or Valsalva-like maneuvers

25. Considerations for Activity Limitation in Diabetic Retinopathy (DR) Level of DR Acceptable Activities Discouraged Activities Ocular Reevaluation No DR Dictated by medical status Dictated by medical status 12 months Mild NPDR Dictated by medical status Dictated by medical status 6-12 months Moderate NPDR Dictated by medical status Activities that dramatically elevate blood pressure: ·Power lifting ·Heavy Valsalva 4-6 months Severe NPDR Dictated by medical status Activities that substantially increase systolic blood pressure, Valsalva maneuvers, and active jarring: ·Boxing ·Heavy competitive sports 2-4 months (may require laser surgery) PDR Low-impact cardiovascular conditioning: ·Swimming ·Walking ·Low-impact aerobics ·Stationary cycling ·Endurance exercises Strenuous activities, Valsalva maneuvers, pounding or jarring: ·Weight lifting ·Jogging ·High-impact aerobcs ·Racquet sports · Strenuous trumpet playing 1-2 months (may require laser surgery) Retinopathy ·NPDR = nonproliferative diabetic retinopathy ·PDR = Proliferative diabetic retinopathy

26. Nephropathy • Specific exercise recommendations have not been developed for patients with incipient or overt nephropathy • High-intensity or strenuous exercise should be avoided

27. Peripheral Neuropathy • Loss of sensation in the feet • Limits weight-bearing exercises Recommended Swimming Bicycling Rowing Chair exercises Arm exercises Other non-weight bearing exercises Contraindicated Treadmill Prolonged walking Jogging Step exercises

28. Autonomic Neuropathy • Cardiac Autonomic Neuropathy • Resting tachycardia • Orthostasis (fall in SBP >20 mmHg upon standing) • Other disturbances in autonomic nervous system function involving the skin, pupils, GI, or genitourinary systems • Sudden death • Silent myocardial ischemia • Hypo/hypertension after vigorous exercise • Difficulty with thermoregulation

29. Effects of Diabetic Autonomic Neuropathy on Exercise • Silent myocardial ischemia • Resting tachycardia and decreased maximal responsiveness • Decreased heart-rate variability • Orthostasis/hypotension with exercise • Exaggerated blood pressure responses with supine position and exercise • Loss of diuranal blood pressure variation

30. Effects of Diabetic Autonomic Neuropathy on Exercise • Cardiovascular and cardiorespiratory instability • Abnormal systolic ejection fractions at rest/exercise • Poor exercise tolerance • Failure of pupil adaption to darkness • Gastroparesis and diabetic diarrhea • Hypoglycemia • Decreased hypoglycemia awareness

31. Effects of Diabetic Autonomic Neuropathy on Exercise • Hypoglycemia unresponsiveness • Heat intolerance due to defective sympathetic thermoregulation and sweating • Susceptibility to foot ulcers and limb loss due to disordered regulation of cutaneous blood flow • Incontinence

32. Exercise Precautions • Postpone exercise if blood glucose >300mg/dL or >240 mg/dL with urinary ketone bodies • Especially when beginning a program, monitor blood glucose before, during, and after exercise if taking insulin or oral agents • Adjustments in carbohydrate intake and/or insulin may be needed before testing and training; ingest carbohydrate if blood glucose is <80-100 mg/dL

33. Exercise Precautions • Select proper footwear and follow appropriate foot care steps to prevent ulcerations and other lesions of the foot • Wear shoes with silica gel or air mid-soles • Wear polyester or blend (cotton/polyester) socks to prevent blisters • Keep the feet dry • Ensure proper fitting footwear

34. Exercise Precautions • Wear a diabetes identification bracelet or shoe tag when exercising, and it should be clearly visible at all times • Avoid extremely hot or cold environments • Maintain proper hydration before, during, and after exercise

35. Exercise Precautions • High resistance exercise using weights are not acceptable for older individuals or those with long standing diabetes • Moderate weight training programs that utilize light weights and high repetitions can be used for all patients with diabetes

36. Guidelines for Avoiding Hypoglycemia • Consume carbohydrates (15-30 g) for every 30 minutes of moderate-intensity exercise • Consume a snack of slowly absorbed carbohydrate following prolonged exercise sessions • Avoid exercising muscle that underlies the injection site of short-acting insulin for 1 hour • Avoid late evening exercise

37. Guidelines for Avoiding Hypoglycemia • Decrease the insulin does: • Intermediate-acting insulin—decrease by 30-35% on the day of exercise • Intermediate- and short-acting insulin—omit the dose of short-acting insulin that precedes exercise • Multiple doses of short-acting insulin—reduce the dose prior to exercise by 30-50% and supplement carbohydrates • Continuous subcutaneous infusion—eliminate the mealtime bolus or increment that precedes or immediately follows exercise

38. Double or blurred vision Abnormally elevated pulse Fatigue Hand tremors / shakiness Headache Mental confusion Poor physical coordination Tingling of hands or tongue Visual spots Weakness Common Hypoglycemic Symptoms During Exercise

39. Refer to Charts • Factors affecting blood glucose management for acute and chronic exercise • Cardiopulmonary response to symptom-limited graded exercise in diabetics and controls • General Carbohydrate Increases for Endurance Activities

40. Preparing for Exercise • Proper warm-up of 5-10 minutes of aerobic activity at a low intensity level • Stretch for 5-10 minutes, primarily focusing on muscles that will be used during the exercise session • Cool down after the exercise session, taking about 5-10 minutes to gradually bring the heart rate down to its preexercise level

41. Exercise Prescription • Frequency: 4-6 days per week or daily at low to moderate intensity • Duration: 20-60 minutes per session • Intensity: 50-85% VO2max • May need to use perceived exertion as an adjunct to heart rate for monitoring exercise intensity. • Exercising late in the evening increases risk of nocturnal hypoglycemia • Exercise caution when exercising in hot weather